Lubricating oil compositions containing viscosity index improving agents



United States Patent 6 Claims. (Cl. 252-59) This invention relates tonew compositions of matter having improved viscosity indexcharacteristics; in particular, this invention is directed to newcompositions of matter which are effective to improve theviscosity-temperature characteristics, that is, the viscosity index(V.I.), of lubricating oil compositions.

This patent application is a division of patent application Serial No.773,176, filed November 12, 1958, now Patent Number 2,999,120, issuedSept. 5, 1961.

The greater proportion of oils obtainable by refining processes anduseful as base oils for lubricating oil compositions have widevariations in viscosity characteristics with changes in temperature.They do not have agents specifically incorporated therein for thepurpose of imparting reduced changes in viscosity with changes intemperature. That is, at a particular temperature, a lubricating oil maybe quite viscous, while at higher temperatures the lubricating oil mayhave a viscosity of a fluid such as kerosene. -In order that theviscosity of a lubricating oil composition will not change rapidly withchanges in the temperature of an internal combustion engine, forexample, numerous additives have been designed to modify theviscosity-temperature characteristics of lubricating oils. The changesin the viscosity occurring with variations in temperature are kept at aminimum.

It is a primary object of this invention to provide new lubricating oilcompositions containing new V.I. improving agents.

In accordance with this invention, it has been discovered thatlubricating oil compositions are improved by incorporating therein newviscosity index improving agents, which are obtained by'treating certainparticular alpha, omega-diaryl alkanes with anhydrous aluminum chloride.The new viscosity index improving agents are the products obtained bytreating alpha, omega-diphenyl alkanes with aluminum chloride.

The present invention comprises broadly the treatment of alpha,omega-diaryl alkanes with anhydrous aluminum chloride to produce oilsoluble products which are useful as V.I. improvers for lubricating oilcompositions, including lubricating oil compositions used in anatmosphere of nuclear radiation.

The alpha, omega-diaryl alkanes are represented by the formula wherein Ris a saturated hydrocarbon radical, including an aliphatic radical,containing from 6 to 12 carbon atoms; B is an aromatic radical; A is ahydrocarbon substituent on the aromatic nucleus containing from 1 to 8carbon atoms; and n is a number 0 to 3.

For purposes of this invention, it is preferred that R is an aliphaticradical containing from 6 to 12 carbon atoms, B is a phenyl radical, Ais a saturated hydrocarbon radical containing from 1 to 8-carbon atoms,and n is a number from O to 3.

The R radicals include the divalent radicals 'obtained from hexane,heptane, octane, nonane, decane, dodecane,

etc.

The B radicals include the following radicals: phenyl, biphenyl,naphthyl, tetralin, etc.

,. ICC

The A radicals include methyl, ethyl, propyl, isopropyl, butyl,tert-butyl, pentyl, hexyl, sec-hexyl, etc.

The alpha, omega-diaryl alkanes are exemplified by 1,6- diphenylhexane;1,7-diphenylheptane; 1,8-diphenyloctane; 1,9-diphenylnonane;1,10-diphenyldecane; .1,9 bis(isopropylphenyl) nonane;1,9-bis(n-butylphenyl) nonane; 1,9-bis(sec-butylphenyl) nonane;1,9-bis(tert-butylphenyl) nonane; 1,6-bis(sec-hexylphenyl) hexane;1,9-bis(1,2,3,4- tetra-hydronaphthyl) nonane; 1,9-bis(biphenyl) nonane,etc. When the aromatic radicals are phenyl radicals, the phenyl nucleusmay be substituted with from 1 to 3 alkyl groups, such alkyl groupsbeing on one or both of the benzene rings. Such al-kyl substituents maybe exemplified by n-propyl, isopropyl, n-butyl, isobutyl, secbutyl,tert-butyl, amyl, etc.

Preferably, the alpha, o-mega-diaryl alkanes are alpha, omega-diphenylalkanes, wherein the alkane radicals contain from the 6 to 12 carbonatoms, and the phenyl nucleus, in each instance, is unsubstituted.

The anhydrous aluminum chloride which is used in the formation of theviscosity index agents according to this invention is used in amounts of8 mol per-cent to mol percent, based on the alpha, omega-diaryl alkane.It is preferred to use from 8 mol percent to about 10 mol percent ofanhydrous aluminum chloride per mol of alpha, omega-diaryl al kane.

A small amount of chloroform may be used with the aluminum chloride, forexample, from about 10 mol percent to about 50 mol percent or greater,based on the aluminum chloride.

Other acid catalysts which can be used include AlBr etc.

Lubricating oils which can be used as base oils include a wide varietyof lubricating oils, such as naphthenic base, parafiin base, and mixedbase lubricating oils, other hydro-carbon lubricants, e.g., lubricatingoils derived from coal products, and synthetic oils, e.g., alkylenepolymers (such as polymers of propylene, butylene, etc., and themixtures thereof), alkylene oxide-type polymers (e.g., propylene oxidepolymers) and derivatives, including alkylene oxide polymers prepared bypolymerizing the alkylene oxide in the presence of water or alcohols,e.g., ethyl alcohol, dicarboxylic acid esters (such as those which areprepared by esterifying such dicarboxylic acids as adipic acid, azelaicacid, suberic acid, sebacic acid, alkan'ol succinic acid, fumaric acid,maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol,2-ethyl hexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids ofphosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecylbenzene, tetradecyl benzene, etc.), and dial kyl benzenes (e.g., n-nonyl2-ethyl hexyl benzene); polyphenyls (e.g., biphenyls and terphenyls),alkyl biphenyl ethers, polymers of silicon (e.g., tetraethyl silicate,tetraisopropyl silicates, tetra(4-methyl-2-tetraethyl) silicate, hexyl(4-rnethyl 2-pentoxy) disiloxane, poly(methyl) siloxane,poly(methylphenyl) siloxane, etc.) Synthetic oils of the alkyleneoxide-type polymers which may be used include those exemplified by thealkylene oxide polymers.

The above base oils may be used individually or in combinations thereof,wherever miscible or Wherever made so by the use of mutual solvents.

The reaction temperatures used in the treatment of the alkanes describedhereinabove by the anhydrous aluminum chloride is in the range of 2 C.to about 5.0" C. to as high as C., preferably from about 2 C. to 50 C.

The new V1. improving agents described herein can be used in lubricatingoil compositions in amounts of 1% to 20%, by weight.

The new viscosity index improving agents of this invention can beprepared by treating an alpha, omega-diaryl alkane with from 8 molpercent to 80 mol percent of anhydrous aluminum chloride, based on thealpha, omega-diaryl alkane, at temperatures ranging from 2 C. to about50 C. or higher, after which the mixture is agitated for a period of 2to 48 hours or more at the same temperature. The mixture is then allowedto stand until the temperature reaches room temperature, after which themixture is agitated for another period of time from 2 to 12 hours ormore. The whole mixture can then be left to stand at room temperaturefor a time sufficient to permit a clear separation into 2 phases. Theliquid is then decanted from the aluminum chloride, blended withbenzene, and washed with dilute hydrochloric acid, sodium bicarbonateand water. The resulting benzene solution is then heated to remove thehenzene by distillation, and to recover the reaction products.

The examples set forth hereinbelow exemplify the various conditionsunder which the reaction product which is useful as a viscosity indeximproving agent may be obtained.

EXAMPLE I Viscosity Index Improving Agent Obtained by Aluminum ChlorideTreatment of 1,9-Diphenylnnane A mixture of 140 grams (0.5 mol) of1,9-diphenylnonane, 2 cc. of chloroform (0.025 mol), and 5 grams ofanhydrous aluminum chloride (0.038 mol) was agitated rapidly at atemperature of about 70 C. for a period of 6 hours. 1.5 grams ofanhydrous aluminum chloride (0.013 mol) was added, after which the wholemixture was agitated for another 10 hours at the same temperature,followed by gradual cooling to room temperature; after which the mixturewas agitated for 12 hours, followed by standing at room temperature fora period of 18 hours during which time 2 layers formed. Afterdecantation from aluminum chloride, each layer was blended with benzene,washed with dilute hydrochloric acid, sodium bicarbonate and water.After water washing, the products 'were filtered and the benzene wasremoved by distillation. The aluminum chloride treatment thus yielded 2fractions having the following properties:

Upper Lower Fraction Fraction 1D 1. 5346 1. 5370 Viscosity at 100F.(cs.)- 49 582 Viscosity at 210F. (cs.)- 8.7 45 V.I 143 117 Pour Point, F-58 +10 The upper fraction, which included unreacted 1,9-diphenylnonane,had greatly improved V.I. characteristics, showing an in situ formationof a V.I. improving agent.

The addition of 20%, by weight, of the lower fraction to1,9-diphenyln0nane, yielded a composition having a V1. of 168. A 10%solution yielded a composition having a V.I. of 150.

The original 1,9-diphenylnonane has the following EXAMPLE II ViscosityIndex Improving Agent Obtained by Aluminum Chloride Treatment of1,9-Diphenyln0nane A mixture of 140 grams (0.5 mol) of 1,9-dipheny1-nonane, 2 cc. of chloroform, and 7 grams (0.053 mol) of anhydrousaluminum chloride was agitated violently at a temperature of about 110C. for a period of 8 hours, after which the whole mixture was allowed tostand at room temperature overnight. 1.5 grams of anhydrous aluminumchloride was added, and the mixture was agitated at about 110 C. for aperiod of 4 hours, followed by standing at room temperature for a periodof 18 hours. After decantation of the liquid from the aluminum chloride,the liquid was blended with diethylether, washed with dilutehydrochloric acid, sodium bicarbonate and water. After water washing,the product was filtered, and the product was distilled to remove thediethylether, a low boiling distillate, unreacted nonane, and to recoverthe reaction products. The distillation was carried out to a bottomstemperature of 380 C. at an absolute pressure of 1.4 mm. Hg. Thealuminum chloride treatment described in this example yieldedapproximately 31%, by weight, of a distilled fraction No. l, which wasidentified as unreacted 1,9-diphenylnonane; 23% of a fraction No. 2; and46%, by weight, of a bottoms fraction characterized as follows:

Fraction 2 Bottoms Boiling Pt, C. 121.25 mm. Hg) 306-323 Viscosity at F.(cs. 83 987 Viscosity at 210 F. (cs. 10. 3 56. 7 Pour Point, C 20 V T113 M01 Wt.:

Theory 1 483 1 886 Found 408 847 1 Calculated for:

1 Calculated for a polyalkyl aromatic material having an average of 5benzene rings, including:

EXAMPLE III Viscosity Index Improving Agent Obtained by AluminumChloride Treatment of 1,9-Diphenylnonane A mixture of grams (0.5 mol) of1,9-diphenylnonane, 2 cc. of chloroform (0.025), and 5 grams (0.038 mol)of anhydrous aluminum chloride was agitated violently at a temperatureof 2-5" C. for a period of 2 hours. 1.5 grams of anhydrous aluminumchloride (0.013 mol) was added, after which the whole mixture wasagitated for another 2 hours at the same temperature, followed bygradual warming to room temperature. After the mixture had been agitatedfor 2 hours, it was allowed to stand at room temperature for a period ofabout 18 hours. After decantation of the liquid from the aluminumchloride the liquid was blended with benzene, washed with dilutehydrochloric acid, sodium bicarbonate, and water. After water washing,the product was filtered and heated to remove the benzene and unreacted1,9-diphenylnonane by distillation to a bottoms temperature of 343 C. atan absolute pressure of 0.5 mm. Hg. The bottoms fraction, whichrepresented approximately 35% of the original charge of nonane, had thefollowing properties:

ing characteristics of the product of Example III, the bottoms thusobtained were incorporated into 1,9-diphenylnonane (unreacted) to make acomposition containing 34% bottoms plus 66% of 1,9-dipheny1nonane. Theresulting blend had a viscosity Index of 159. This V.I. of 159represents an increase of 35 points, since the original1,9-diphenylnonane (as set forth in the data of Example I) had a V.I. of124.

EXAMPLE IV Viscosity Index Improving Agent Obtained by Aluminum ChlorideTreatment of 1,9-Diphenylnnane A mixture of 140 grams (0.5 mol) of1,9-diphenylnonane, 2 cc. of chloroform (0.025), and 5 grams (0.038 mol)of anhydrous aluminum choride was agitated violently at a temperature of25 C. for a period of 2 hours. 1.5 grams of anhydrous aluminum chloride(0.013 mol) was added, after which the whole mixture was agitated foranother 2 hrs. after which it was allowed to stand at room temperaturefor a period of about 18 hours. After decantation of the liquid from thealuminum chloride the liquid was blended with benzene, washed withdilute hydrochloric acid, sodium bicarbonate, and water. After waterwashing, the product was filtered and heated to remove the benzene andunreacted 1,9-diphenylnonane by distillation to a bottoms temperature of320 C. at an absolute pressure of 0.5 mm. Hg. The bottoms fraction,which represented approximately 35% of the original charge of nonane,had the following properties:

Viscosity at 100 F. (cs) 110.0 Viscosity at 210 F. (as) 14.4 V.I. 134

wherein R is a saturated hydrocarbon radical having from 6 to 12 carbonatoms, R is a saturated hydrocarbon radical having from 1 to 4 carbonatoms; n is a number from 0 to 3 and X is a number from 2 to 6 orhigher, wherein the average value for X is from 2 to 6, as furtherdescribed and exemplified hereinabove.

I claim:

1. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity and, in an amount sufficient to improve theviscosity index thereof, an agent of the formula:

wherein R is a saturated hydrocarbon radical having from 6 to 12 carbonatoms, R is a saturated hydrocarbon radical having from 1 to 4 carbonatoms, n is a number from 0 to 3, and X is a number from 2 to 6 whereinone of the phenyl radicals is attached to the R radical at the alphacarbon atom and the other phenyl radical is attached to the R radical atthe omega carbon atom.

2. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and from 1% to 20%, by weight, of a viscosityindex improving agent of the formula:

wherein R is a saturated hydrocarbon radical having from 6 to 12 carbonatoms, R is a saturated hydrocarbon radical having from 1 to 4 carbonatoms, n is a number from 0 to 3, and X is a number from 2 to 6 whereinone of the phenyl radicals is attached to the R radical at the alphacarbon atom and the other phenyl radical is attached to the R radical atthe omega carbon atom.

3. The lubricating oil composition of claim 2 wherein said oil oflubricating viscosity is a petroleum oil.

4. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and, in an amount sufficient to improve theviscosity index thereof,

an agent of the formula wherein x is a number from 2 to 6.

5. The lubricating oil composition of claim 4, wherein x is a numberhaving a value of 2.

6. The lubricating oil composition of claim 4, wherein x is a numberhaving a value of 4.

Bowden Feb. 11, 1941 Kemp Apr. 17, 1951

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OILOF LUBRICATING VISCOSITY AND, IN AN AMOUNT SUFFICIENT TO IMPROVE THEVISCOSITY INDEX THEREOF, AN AGENT OF THE FORMULA: